With the improvement of mobile communication technologies, the 3rd Generation Partnership Program (3GPP) has developed mobility (high-speed movement of a terminal device) support, broadband (high-throughput) data communication support, and the like, to enable the transmission of multimedia data such as video as well as sound in order to provide wireless communication services across a very broad range.
In multimedia data communication, data to be transmitted, such as sound and video, is encoded and transmitted to achieve efficiency, stabilization, and the like, at various points, such as the bandwidth consumption of communication channels and the channel properties. As one of such data encoding methods, there is a hierarchical coding technique.
In the hierarchical coding technique, video and sound are classified by quality, intended purpose, or the like, and layered in respective levels so that additional information will be encoded as an information block separable from fundamental data. Each information block can be sent and received individually, and synthesized as required so that one coded data group can be used in various environments. As a precedent method already employed internationally as the hierarchical audio coding technique, there is a technique described in Non-Patent Document 1 cited below. Patent Document 1 also discloses a method of compressing image data different in quality.
In general, the camcorder is designed to enable a camera operator to hold it to perform shooting and recording. The camcorder is relatively small, with means (mostly, a view finder) for checking video shot by the camera operator integrated therein. However, for example, there are cases where camera shake occurs when the camera operator moves his hands holding the camcorder to look through the view finder, or it is difficult to check the shot video from some distance. Patent Document 2 cited below discloses a camcorder equipped with an external unit removable from a camera unit. According to the camcorder disclosed in Patent Document 2, the camera unit is separated from the other units with the connections therebetween made up with communication, whether wired or wireless, to enable shooting corresponding to user's various usage scenes of the digital camcorder.